For a game the size of WoW I'd imagine with the amount of staff, and equipment the break even point would be about 2-3 million subs. So I'd have to guess it will be at least 2 or 3 more years before they have to revamp the revenue model.

I certainly hope they will not make it f2p. They might make 1-60 f2p though (to give people a true taste of the game and it would not hurt them allot)... I also hope more games will stap p2p as I like the p2p model more then the f2p model.